At a meeting in Algiers on Sept. 28, after two days of round-the-clock talks, the Organization of the Petroleum Exporting Countries agreed to the outlines of its first oil production cut in eight years. Ministers said that the group, which supplies about 40 percent of the world’s oil, will drop production to between 32.5 million and 33 million barrels a day. Most details, however, have yet to be agreed upon.